JP2010262455A - Management apparatus, information generation program, and information generation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To generate management information by which falsification of a record such as attribute information of content data can be reliably prevented and efficiency of retrieving management information such as content catalog information can be increased. <P>SOLUTION: A management apparatus generates leaf page information including one or more records, generates root page information including falsification check information for checking falsification of child page information in the position of a child of root page information, or a record in the position of a child of the root page information, and a serial number of the child page information in the position of the child of the root page information, generates node page information including falsification check information for checking falsification of child page information in the position of a child of node page information, or a record in the position of a child of the node page information, positioned between the root page information and the leaf page information, and a serial number of the child page information in the position of the child of the node page information, and stores the root page information, the node page information and the leaf page information, in a tree structure. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a data structure for searching or managing desired content data. Specifically, the present invention relates to a data structure and a search technique that can reliably prevent alteration of records such as attribute information of content data.

  In this type of content distributed storage system, each node device uses content catalog information in which attribute information of content data is described. Each node device can retrieve desired content data and acquire it from other node devices or content management servers. This attribute information includes information such as a content name, a publication start time, a publication end time, and a search keyword for content data. The content catalog information is generated by the content management server and distributed to each node device. Also, in the content distributed storage system, when new content data is added, or when the use of content data ends, the content catalog information is updated by the content management server and distributed to each node device.

  By the way, as the number of content data that can be used in the content distributed storage system increases, the data amount of content catalog information also increases. For this reason, there is a problem that the content catalog information cannot be stored in one node device. In order to solve this problem, Patent Document 1 proposes a configuration in which a plurality of node devices distribute and store a plurality of content catalog information.

JP 2007-280303 A

  As described above, when each node device stores divided content catalog information, it is necessary to give an electronic signature to each attribute information of each content data in order to prevent falsification of the content catalog information.

  In addition, when adding, updating, or deleting attribute information of content data to the content catalog information, it is necessary to search the content catalog information. That is, it is necessary to search for a position where content catalog information to be added, updated or deleted is inserted or deleted. Conventionally, since almost all desired content data is searched from a list of content catalog information to which an electronic signature has been applied, efficiency has been low.

  The present invention has been made in view of the above problems and the like. A management device for generating management information that can reliably prevent falsification of records such as attribute information of content data and can improve the search efficiency of management information such as content catalog information, an information generation program, and It is an object to provide an information generation method.

  In order to solve the above problem, the invention according to claim 1 is a page information storage means for storing a plurality of page information as a tree structure in association with the root page information located at the root to the leaf page information located at the leaf. And leaf page information generation means for generating the leaf page information including one or a plurality of records, and child page information at the child position of the root page information or falsification of the record at the child position of the root page information. Falsification check information for checking and root page information generating means for generating the root page information including a child page information serial number at a child position of the root page information; and the leaf page information from the root page information For checking whether the record at the child position of the section page information located between or the record at the child position of the section page information is falsified. Node page information generating means for generating the node page information including check information and a child page information serial number at a child position of the node page information, and the page information storage means includes the root page information. The node page information and the leaf page information are stored in the tree structure.

  According to the present invention, leaf page information including one or a plurality of records is generated. Further, root page information including child page information of the root page information or tampering check information for checking the tampering of the record at the child position of the root page information and the serial number of the child page information of the root page information is generated. The Also, node page information including child page information of child of node page information or falsification check information for checking falsification of record at child position of node page information, and serial number of child page information of node page information. Generated. As a result, it is possible to check the falsification of the record and to prevent unauthorized insertion / replacement of outdated regular page information. A plurality of page information including the generated root page information, node page information, and page information is stored in a tree structure.

  Therefore, by managing records in a tree structure, it is possible to check for falsification of records and to reduce the time for record search processing.

  According to a second aspect of the present invention, root link information including a serial number of the root page information and falsification check information for checking falsification of the root page information, and checking falsification of the root link information Root link information generating means for generating an electronic signature for performing, and the page information storage means includes the root link information, the root page information, the node page information, and the leaf page information as the tree. It is memorized in a structure.

  According to the present invention, the check information for checking the falsification of the child page information is held by the parent page information. The root link information holds the root page information falsification check information. The root link information has an electronic signature, and tampering can be strictly checked by the electronic signature. Previously, it was necessary to apply digital signatures to all records, but by applying digital signatures only to root link information, the digital signature of the root page is verified in order to guarantee tampering of the records located in the child. This can be confirmed. Therefore, the message digest as described in the embodiment can be used as the falsification check information of each root page information and node page information stored in the storage means, and the data amount of each record is reduced. In addition, since a process for applying an electronic signature to each record is not necessary, an electronic signature process becomes unnecessary.

  According to a third aspect of the present invention, the root page information generating means is responsible for index information corresponding to one or a plurality of page information having a parent-child relationship with the root page information as a parent in the tree structure. And the node page information generation means determines the node information of the index information of one or more page information having a parent-child relationship with the node page information as a parent in the tree structure. The additional input means for further generating the assigned area information to be shown and inputting the additional record to be added and the index information of the record, the index information input by the additional input means, and the root page information or the node page An additional leaf page determining means for determining the leaf page information for registering the additional record based on the responsible area information of the information; Registration means for registering the additional record in the leaf page information determined by the additional leaf page determination means, assignment means for assigning a new serial number to the leaf page information determined by the additional leaf page determination means, and the addition An additional update means for updating the serial number and the check information of the node page information and the root page information from the leaf page information in which a record is registered to the root page information, based on the registration of the additional record; It is characterized by providing.

  According to the present invention, leaf page information for registering an additional record is determined based on the input index information and the assigned region information of root page information or node page information. An additional record is registered in the determined leaf page information. Also, a new serial number is assigned to the determined leaf page information. Then, the serial number and check information of the node page information and the root page information from the leaf page information to which the additional record is registered and the root page information are updated based on the registration of the additional record.

  Therefore, a record can be easily added to the leaf page information in the tree structure.

  According to a fourth aspect of the present invention, the additional page determining unit includes a determining unit that determines whether the additional record can be registered in the determined leaf page information, and the additional record is registered by the determining unit. When it is determined that it is impossible, the leaf page information generation unit generates new leaf page information, the registration unit registers the additional record in the newly generated leaf page information, and The assigning means assigns a new serial number to the newly generated leaf page information, and the additional update means assigns the node page information and the root page information from the newly generated leaf page information to the root page information. The serial number and the check information with page information are updated based on registration of the additional record.

  According to the present invention, when the additional record cannot be registered in the leaf page information determined as the leaf page information for registering the additional record, new leaf page information is generated. Then, an additional record is registered in the new leaf page information. Also, a new serial number is assigned to the new leaf page information. Then, the serial number and check information of the node page information and the root page information from the leaf page information to which the additional record is registered and the root page information are updated based on the registration of the additional record.

  Therefore, even if the additional record cannot be registered in the leaf page information, the additional record can be registered in the newly generated leaf page information.

  According to a fifth aspect of the present invention, the root page information generating means further includes responsible area information indicating a responsible area of index information of page information having a parent-child relationship with the root page as a parent in the tree structure. The node page information generation means further generates assigned region information indicating an assigned region of index information of page information in a parent-child relationship with the node page information as a parent in the tree structure, and is deleted The delete record is registered based on the delete input means for inputting the index information of the delete record, the index information input by the delete input means, and the assigned area information of the root page information or the node page information Deleted leaf page determining means for determining the leaf page information to be executed and the leaf page information determined by the deleted leaf page determining means before The serial number and the check information with the node page information to the root page information and the root page information, characterized in that it comprises a and a deletion updating means for updating, based on the determination of the leaf page information.

  According to the present invention, leaf page information for registering a deletion record is determined based on the input index information and the assigned area information of root page information or node page information. The serial number and check information of the node page information and the root page information from the determined leaf page information to the root page information are updated.

  Therefore, for example, it is possible to eliminate a record that becomes old and is to be deleted.

  According to a sixth aspect of the present invention, the leaf page information includes index information for searching for the record included in the leaf page information, and the root page information generation unit includes: The node page information generation means further generates the assigned region information indicating the assigned region of the index information of the page information having a parent-child relationship with the root page as a parent, and the node page information generation means sets the node page information as a parent in the tree structure. The search input means for generating the assigned area information indicating the assigned area of the index information of the page information in the relationship between the parent and the child and inputting the index information of the search record to be searched, and input by the search input means Index of the search record based on the index information and the area information of the root page information or the node page information. Characterized in that it comprises a retrieval means for retrieving information.

  According to the present invention, the index information of the search record is searched based on the input index information and the assigned area information of the root page information or the node page information.

  Therefore, a search target record can be quickly searched.

  In the invention according to claim 7, in order to manage a plurality of page information as a tree structure, the child page information of the child position of the root page information located at the root in the tree structure or the child position of the root page information A root page information generation step for generating the root page information including falsification check information for checking falsification of the record and a serial number of the child page information at the child position of the root page information; and one or a plurality of records Leaf page information generation step for generating leaf page information including the child page information at the child position of the node page information located between the root page information and the leaf page information in the tree structure or the node page information Serial number of the falsification check information for checking the falsification of the record at the child position of the child page information and the child page information of the child position of the section page information Page information that stores the node page information including the node page information generation step, the root page information, the node page information, and the leaf page information as the plurality of page information in the tree structure. The storage step is realized by a computer.

  In the invention according to claim 8, in order to manage a plurality of page information as a tree structure, the child page information of the child position of the root page information located at the root in the tree structure or the child position of the root page information A root page information generation step for generating the root page information including falsification check information for checking falsification of the record and a serial number of the child page information at the child position of the root page information; and one or a plurality of records Leaf page information generation step for generating leaf page information including the child page information at the child position of the node page information located between the root page information and the leaf page information in the tree structure or the node page information Serial number of the falsification check information for checking the falsification of the record at the child position of the child page information and the child page information of the child position of the section page information Page information that stores the node page information including the node page information generation step, the root page information, the node page information, and the leaf page information as the plurality of page information in the tree structure. And a storing step.

  According to the present invention, by managing records with a tree structure, it is possible to check for falsification of records and to reduce the time for record search processing.

It is a figure which shows an example of the connection aspect of each node apparatus in the content distribution storage system S which concerns on one Embodiment. It is a figure which shows an example of the structure of the content catalog information which concerns on one Embodiment. It is a figure which shows an example of a catalog information state in an initial state, and a mode that catalog information is updated when a record is added. It is a figure which shows an example of a mode that catalog information is updated when a record is added. It is a figure which shows an example of a mode that catalog information is updated when a record is added. It is a figure which shows an example of a mode that catalog information is updated when a record is deleted. It is a figure showing an example of outline composition of center server SA concerning one embodiment. It is a figure showing an example of outline composition of node Nn concerning one embodiment. It is a flowchart which shows the process example of the control part 11 in center server SA which concerns on one Embodiment. It is a flowchart which shows the process example in the root link information registration process of the control part 11 in center server SA which concerns on one Embodiment. It is a flowchart which shows the process example in the page information registration process of the control part 11 in center server SA which concerns on one Embodiment. It is a flowchart which shows the process example in the record addition process of the control part 11 in center server SA which concerns on one Embodiment. It is a flowchart which shows the process example in the record deletion process of the control part 11 in center server SA which concerns on one Embodiment. It is a flowchart which shows the process example in the page information acquisition process of the control part 11 in center server SA which concerns on one Embodiment. It is a flowchart which shows the process example in the record search process of the control part 11 in center server SA which concerns on one Embodiment. It is a flowchart which shows the process example of the control part 21 in the node Nn which concerns on one Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiment described below is an embodiment when the present invention is applied to a content distributed storage system.

[1. Outline and configuration of distributed content storage system]
First, with reference to FIG. 1 etc., the structure and operation | movement outline | summary of the content distribution preservation | save system which concern on this embodiment are demonstrated.

  FIG. 1 is a diagram showing an example of a connection mode of each node device in the content distributed storage system S according to the present embodiment.

  As shown in the lower frame 101 of FIG. 1, the distributed storage system S is configured by connecting a plurality of node devices Nn via the Internet. Further, as shown in a lower frame 101 of FIG. 1, IX (Internet eXchange) 3, ISP (Internet Service Provider) 4a, 4b, DSL (Digital Subscriber Line) line provider devices 5a, 5b, FTTH (Fiber To A network 8 such as the Internet is constructed by the device 6 of the line provider, the communication line 7 and the like. The network 8 is a real-world communication network. Note that a router for transferring data packets is appropriately inserted in the network 8 in the example of FIG. 1, but is not shown in FIG. 1. For example, a telephone line or an optical cable is used as the communication line 7.

  A plurality of node devices Nn (n = 1, 2, 3,...) Are connected to such a network 8. Hereinafter, the node device is referred to as a “node”. Each node Nn is assigned a unique manufacturing number and an IP (Internet Protocol) address. Then, the content distributed storage system S according to the present embodiment is a peer-to-peer network system formed by connecting any of a plurality of nodes Nn, as shown in the upper frame 100 of FIG. It has become.

  The network 9 shown in the upper frame 100 of FIG. 1 is an overlay network 9 that configures a virtual link formed using the existing network 8. The overlay network 9 which is a logical network is realized by a specific algorithm, for example, an algorithm using DHT. Each node Nn connected to the content distributed storage system S is assigned a node ID, which is unique identification information having a predetermined number of digits.

  The node ID is, for example, a value obtained by hashing an IP address or manufacturing number individually assigned to each node Nn using a common hash function. The node IDs are arranged in a distributed manner in the ID space. For example, SHA-1 or the like is used as the hash function. The hashed value has a bit length of 160 bits, for example. The node IDs are distributed in the ID space without being distributed.

  In connection with the content distributed storage system S, a node Nn that is not connected, for example, the node N8 transmits a participation message indicating a request to participate in the content distributed storage system to any connected node Nn. Is done by doing. The participation in the content distributed storage system S means that the node device Nn is connected to the distributed storage system S and content data can be acquired from the distributed storage system S. The arbitrary node Nn is, for example, a contact node that is always connected to the system S.

  Each node Nn holds a routing table using DHT. This routing table defines the transfer destinations of various messages on the content distributed storage system S. Specifically, a plurality of pieces of node information including node IDs, IP addresses, and port numbers of nodes Nn that are moderately separated in the ID space are registered in this routing table.

  One node connected to the content distributed storage system S stores the minimum necessary node information of the node Nn as a routing table. By transferring various messages between the nodes Nn, node information about the node Nn that does not store node information is acquired.

  Such a routing table using DHT is well known in Japanese Patent Application Laid-Open No. 2006-197400 and the like, and will not be described in detail.

  The content distributed storage system S stores various content data replicas having different contents in a predetermined file format in a distributed manner in a plurality of nodes Nn. Hereinafter, the content data is referred to as “content”. A replica can be used between the nodes Nn. The original of each content is stored in the center server SA. For example, a replica of the content of a movie with the title XXX is stored in the node N5. On the other hand, a replica of the movie content whose title is YYY is stored in the node N3. In this way, it is distributed and stored in a plurality of nodes Nn. Hereinafter, the node N in which the content replica is stored is referred to as a “content holding node”.

  Information such as a content name and content ID, which is unique identification information for each content, is added to each content replica described above. This content ID is generated, for example, by hashing the content name + an arbitrary numerical value with a hash function common to the case of obtaining the node ID. Alternatively, the system administrator may give a unique ID value for each content.

  The location of the content replicas that are distributed and stored is stored as index information by the node Nn or the like that manages (stores) the location of the content replicas. Hereinafter, the node Nn that manages (stores) the location of the replica is referred to as a “root node”. The index information includes a set of node information of the node Nn that stores the replica, a content ID of the content, and the like. Such a root node is determined to be a node Nn having a node ID closest to the content ID, for example. The node ID closest to the content ID is, for example, the node ID with the highest number of upper digits that match.

  For example, index information about a replica of a movie content whose title is XXX is managed by the node N4 which is the root node of the content. Further, for example, index information about a content replica of a movie whose title is YYY is managed by the node N7 which is the root node of the content. Further, such a root node is determined to be a node Nn having a node ID closest to the content ID, for example. The node ID closest to the content ID is, for example, a node ID that matches the content ID more frequently with the upper digits.

  When a user of a certain node Nn wants to obtain a replica of the desired content, the node Nn that desires to obtain this replica generates a message. Hereinafter, the node Nn that the user desires to acquire a replica is referred to as a “user node”. This message is a content location inquiry message including the content ID of the content desired to be acquired and the IP address of the user node. The content location inquiry message is also a message for searching for a content holding node. The above-described content location inquiry message is sent to another node Nn according to the DHT routing table acquired by the user node. That is, the user node sends a content location inquiry message toward the root node. As a result, the content location inquiry message finally arrives at the root node by DHT routing using the content ID as a key.

  In each node Nn, attribute information such as content name and content ID of the content is described in the content catalog information. The content catalog information is created by the center server SA and distributed to all nodes Nn in page information units described later. Details of the structure, content, and creation method of the content catalog information will be described later.

  The content ID included in the content location inquiry message may be generated by the user node by hashing the content name with the common hash function. The DHT routing is known in Japanese Patent Application Laid-Open No. 2006-197400 and the like, and thus detailed description thereof is omitted.

  The root node that has received the content location inquiry message obtains index information corresponding to the content ID included therein from the index information cache. The acquired index information is returned to the user node that is the transmission source of the content location inquiry message. The user node that has acquired the index information in this way can download (acquire) a replica of the content based on the index information. The user node accesses the content holding node based on the IP address of the content holding node included in the index information. A content replica can be downloaded from the accessed content holding node. In this case, the user node selects one content holding node from among the plurality of content holding nodes. The user node can then connect to the selected content holding node and download a replica of the content.

  The root node transmits a content transmission request message to the content holding node indicated by the IP address or the like included in the index information, whereby the user node downloads the replica from the content holding node. You can also. In addition, the user node can obtain the index information from a cache node that caches the same index information as the root node until the content location inquiry message reaches the root node.

  Further, when the user node acquires and stores a replica of the content from the content holding node, the stored user node generates a publish message. The publish message is a message for informing the root node that the replica has been saved. The publish message includes the content ID of the replica and the node information of the node device that stores the replica. The publish message is sent toward the root node. As a result, the publish message arrives at the root node by DHT routing using the content ID as a key, like the content location inquiry message. Then, the root node receives the publish message. The root node stores index information including a set of node information and content ID included in the publish message in the index information cache area. In this way, the user node becomes a new content holding node that holds a replica of the content.

[2. Content catalog information structure and contents]
Next, the structure and contents of the content catalog information will be described with reference to FIG.

  FIG. 2 is a diagram showing an example of the structure of content catalog information according to the present embodiment. The content catalog information is simply referred to as catalog information in the future.

  The catalog information is information for managing content attribute information as a list. The content of this attribute information is stored in the record. The catalog information is information that can uniquely identify the content from the search key. To be able to specify content means to be able to find a record of the content. As the search key, for example, a value obtained by hashing corresponding records and content names with a common hash function is used. Alternatively, the search key may be a content ID, a content name, or the like. This search key is an example of index information.

  The catalog information used in the present embodiment has a search tree structure shown in FIG. 2 in order to prevent falsification of content attribute information and to efficiently search for content.

  As shown in FIG. 2, the catalog information is configured by associating each page information from root page information located at the root in the tree structure to leaf page information located at the leaf. The root page information is an example of root page information. The directly associated page information forms a parent-child relationship. It is assumed that page information Y is associated with certain page information X. That is, the page information X and the page information Y form a parent-child relationship. Of the page information X and page information Y, when the page information X is shorter in distance from the root page information, the page information X is the page information of the parent located at the parent when viewed from the page information Y. Then, the page information Y becomes page information of a child positioned as a child as viewed from the page information X. Here, the distance from the root page information is a length corresponding to the number of links from the root position to the node of interest in the tree structure. In other words, the distance from the root page information corresponds to the number of page information that passes through the page information to be noticed by tracing the association from the root page information to the noticed page information. In the following description, parent page information is referred to as parent page information, and child page information is referred to as child page information.

  The association between the parent page information and the child page information is indicated in the link information. The link information is information stored in the parent page information and is information indicating child page information. This link information includes the page number of the child page information and a message digest for checking the alteration of the child page information.

  The page number is a serial number uniquely assigned to page information. The page information indicated by the link information means page information to which a page number included in the link information is assigned. Although details will be described later, when certain page information is updated, a new page number is assigned to the page information. Here, the update of the page information in the present embodiment means that the page information in which the content of the original page information is updated is newly created as page information different from the original page information. Actually, the page number corresponds to, for example, a storage address when the page information is stored in the RAM, or a storage address of a pointer indicating a storage position of the page information. When page information is saved as a file, the page number corresponds to the file name.

  The message digest is information for checking falsification of a record stored in the child page information indicated by the link information or the child page information indicated by the link information. The message digest is a value obtained by hashing a target to be checked for tampering with a common hash function. This message digest is an example of falsification check information.

  The catalog information further includes root link information (reference numeral 100). In the root link information, link information to the root page information is stored (reference numeral 1001). The link information includes the page number (reference numeral 1002) of the root page information and the message digest (reference numeral 1003). The root link information stores an electronic signature (reference numeral 1004). The electronic signature is information for checking whether the root link information is falsified. The electronic signature includes information such as a signature value and certificate information, for example.

  The page information is roughly classified into node page information (reference numeral 200) and leaf page information (reference numeral 300).

  The node page information has one or more child page information. The node page information stores self-link information (reference numeral 2001), link information to the child page information (reference numeral 2004), and an index (reference numeral 2007). The self link information is link information to the node page information itself in which the self link information is stored. That is, the self-link information includes the page number (reference numeral 2002) of the node page information and the message digest (reference numeral 2003). Therefore, the self-link information has the same content as the link information to the node page information stored in the parent page information of the node page information.

  The link information to the child page information includes the page number (symbol 2006) and the message digest (symbol 2005) of the child page information. In the node page information, the simple link information means link information to child page information, not self-link information. A plurality of link information can be stored in the node page information. The maximum number of link information that can be stored in one section page information matches the degree of the tree structure of the catalog information. This order means the maximum number of children that a parent can have. That is, the order corresponds to the value n of the n-ary search tree.

  An index has the same role as information called a value, key, etc., held by nodes of a search tree. This index is information for searching for page information in which content records are stored using a search key. The index shown in FIG. 2 is shown in decimal numbers for convenience. This index is an example of index information and assigned area information.

  The tree structure of catalog information has order. Therefore, the indexes stored in the node page information are arranged in ascending order of the values, for example. The link information is arranged in the order corresponding to the index. For example, the first link information indicates an association with child page information in which a range index equal to or less than the value of the first index is stored. For example, the second link information indicates association with child page information in which an index in a range larger than the value of the first index and less than or equal to the value of the second index is stored. When k pieces of link information are currently stored in certain node page information, k-1 indexes are stored in the node page information.

  As described above, the leaf page information is page information located on a leaf in the search tree. That is, the leaf page information has no child page information. In the leaf page information, self-link information (reference numeral 3001), a record (reference numeral 3004), and an index (reference numeral 3005) are stored. The self link information is link information to the leaf page information itself in which the self link information is stored. That is, the self-link information includes the page number (reference numeral 3002) of the leaf page information and the message digest (reference numeral 3003). Therefore, the self-link information has the same content as the link information to the leaf page information stored in the parent page information of the leaf page information.

  Records and indexes are associated one-on-one. One or more pairs of records and indexes associated with each other are stored in the leaf page information. One record is set with attribute information of one or a plurality of contents. For example, a content ID, a content start date / time, a content end date / time, a content name, a keyword, and the like are set in the record. The index is information for uniquely identifying the corresponding record. The type of information used as an index of leaf page information is the same as the type of information used as an index of node page information. When a content ID, content name, or the like is used as this index, this information need not be included in the setting contents of the record. This index is an example of index information.

  The reason why the content search can be efficiently performed when the catalog information having the configuration described above is used will be described. When the number of registered contents is n, the search calculation amount in the sequential search is the worst O (n). On the other hand, since the catalog information according to the present embodiment has a search tree structure, the calculation amount of the search in a state where the tree is balanced is O (log n) as is well known. Therefore, content can be searched efficiently.

  Next, the reason why falsification of content attribute information can be prevented will be described. Whether or not the child page information is falsified is determined by link information to the child page information stored in the parent page information. That is, since the link information includes the message digest of the child page information, the tampering check is performed using this message digest. In this way, whether or not the child page information is falsified from the leaf page information to the root page information is checked by the link information stored in the parent page information. Whether the root page information is falsified is checked by the root link information.

  Generally, it is said that tampering cannot be reliably prevented only by a message digest. That is, if a necessary hash function can be obtained, a message digest can be calculated. This hash function is disclosed for tampering check on the node Nn side, for example. A malicious person can tamper with the contents of the page information and calculate a message digest with the tampered contents. If this message digest is set in the link information of the parent page, it is not known whether or not it has been tampered with.

  On the other hand, in the catalog information according to the present embodiment, an electronic signature for guaranteeing the authenticity is given to the root link information. For example, when a public key method is used for an electronic signature, falsification of root link information can be checked if a secret key required for the electronic signature is not obtained by a third party. If the root link information is determined to be authentic by falsification check using an electronic signature, the message digest of the root page information included in the root link information can also be determined to be authentic. Next, if the root page information is determined to be authentic by the falsification check using this authentic message digest, the message digest of the child page information included in the link information stored in the root page information is also authentic. It can be judged. In this way, the authenticity of the child page information is guaranteed by the message digest of the link information stored in the parent page information from the root page information to the leaf page information. As a result, falsification of the entire catalog information can be prevented.

  In the present embodiment, as described above, an electronic signature is created only for the root link information, but creating an electronic signature for all the page information is not excluded. However, electronic signatures are generally created by setting information such as certificate information, so that the security of electronic signatures is generally higher than that of message digests. The amount of calculation required for processing such as encryption for improving security and decryption at the time of tampering check is large, and the amount of data necessary for electronic signature such as electronic certificate information is also large. Therefore, the message digest can save both the calculation amount and the data amount of the page information than the electronic signature. On the other hand, when creating an electronic signature for all page information, root link information is not essential. In this case, an electronic signature for the root page information may be stored.

  As the alteration of the catalog information, in addition to the above-described alteration of the content of the page information itself, there is an alteration in which the page information is replaced with old page information. In other words, the content of the page information is updated by adding or deleting content, but this is replaced with the page information before being updated. The old page information itself is also authentic. Therefore, it is necessary to be able to distinguish which page information is the latest.

  In the catalog information according to the present embodiment, a page number is assigned to each page information. The same page number is not assigned between page information. Further, in the present embodiment, when the page information is updated, the contents of the page information are not rewritten. In the present embodiment, new page information is created separately from the original page information, and updated content is set for the new page information. At this time, a new page information is assigned a page number different from the page number of the original page information. Specifically, each time new page information is created, the latest page number that is not assigned to any page information created in the past is assigned. For example, if the page number assigned last is 100, the page number assigned to the newly created page information is 101. This page number is set in the link information stored in the parent page information. Therefore, the link information stored in the node page information always indicates the latest child page information. If the page number of the link information is tampered with an old page number, it is a tampering of the contents of the page information. Therefore, falsification can be found by the above method.

  In this embodiment, when updating page information, new page information is created as described above, but the contents of the page information itself may be rewritten.

  The structure of the catalog information described with reference to FIG. 2 is merely an example. As the structure of the catalog information, any structure may be used as long as it has a tree structure capable of searching for content records.

  For example, a record may be stored not only in leaf page information but also in node page information. The order of the tree structure, that is, the maximum number of link information that can be stored in one node page information is arbitrary. The maximum number of records that can be stored in one page information may be one or more. Furthermore, self-link information is not essential.

  Furthermore, the index of node page information is not essential. For example, in the case of a trie tree, an index of node page information is not necessary. That is, in the trie tree, the position of the page information on the tree structure corresponds to the index, and the tree is traced from the root page information to the leaf page information according to the values of the search key bits and characters. For example, assume that 4 bits from the most significant 4 bits of the search key are assigned to each node page information from the root page information to the leaf page information. In this case, there is an array that stores 16 pieces of link information as elements in one node page information. For example, when the search key is F3405B9C in hexadecimal, with respect to the root page information, F in the upper first digit is an array index. That is, the 16th link information stored in the array in the root page information becomes the link information to the child page information to be referred to next. Next, regarding the child page information of the root page information, 3 in the second digit from the top is an array index. That is, the fourth link information stored in the array in the child page information is the link information to the child page information to be traced next. When the leaf page information is reached in this way, the entire search key is compared with the record index. In this way, the search is performed.

  Furthermore, an index of leaf page information is not essential. For example, in a trie tree, it is possible to collect records that have relatively different index values. For example, it is assumed that there is a record of F3405B9C and a record of F34013A2 with an index of hexadecimal. The upper three digits of the two indexes are the same. In this case, if there is no other record whose upper three digits are F34, and one leaf page information can store two or more records, the two records are stored in the same leaf page information. can do. That is, two records are stored in the leaf page information that follows F, 3, 4 from the root page information. In this case, a record index is required for leaf page information. On the other hand, for example, it is assumed that the node page information is always created for the upper 7 digits of the search key, and the lowest 4th digit value of the search key is assigned to the leaf page information. In this case, the leaf page information includes an array that stores 16 records as elements. At this time, the record whose index is F3405B9C is stored in the 10th position of the array in the leaf page information that traces F, 3, 4, 0, 5, B, 9 from the root page information. In this case, the leaf page information does not require a record index.

  Furthermore, a specific example is shown and demonstrated. Here, it is assumed that 4-digit quaternary numbers are used as the content index. In this case, each link page can store four pieces of link information. For example, the root page information includes an array that stores link information that points to page information corresponding to the values of the upper one digit of the index corresponding to 0, 1, 2, and 3, respectively. In this case, the link information to the page information corresponding to the value of the highest one digit of the index corresponding to 0 is stored at the position corresponding to the value of the most significant digit. In addition, the link information to the page information corresponding to the value of the highest one digit of the index corresponding to 1 is stored at the position corresponding to the value of the most significant digit. In addition, the link information to the page information in which the value of the highest one digit of the index corresponds to 2 is stored at the position corresponding to the value of the most significant digit of 2. In addition, the link information to the page information corresponding to the value of the highest one digit of the index corresponding to 3 is stored at the position corresponding to the value of the most significant digit of 3.

  Next, for example, in the page information in which the upper one digit value of the index corresponds to 1, link information indicating the page information corresponding to the upper two digit values of the index corresponding to 10, 11, 12, and 13 is stored. There is an array. In this case, the link information to the page information corresponding to the value of the upper two digits of the index corresponding to 10 is stored at the position corresponding to the value of the second most significant digit. Also, the link information to the page information corresponding to the value of the upper two digits of the index corresponding to 11 is stored at the position corresponding to the value of the second most significant digit. Further, the link information to the page information corresponding to the value of the upper two digits of the index corresponding to 12 is stored at the position where the value of the second most significant digit corresponds to 2. Also, the link information to the page information corresponding to the value of the upper two digits of the index corresponding to 13 is stored at the position corresponding to the value of the second most significant digit.

  Next, for example, the page information corresponding to the upper two digits of the index corresponding to 10 stores link information indicating the page information corresponding to the upper three digits of the index corresponding to 100, 101, 102, and 103, respectively. There is an array. In this case, the link information to the page information corresponding to the value of the upper three digits of the index corresponding to 100 is stored at the position corresponding to the value of the third digit from the highest.

  Next, for example, page information in which the upper three digits of the index correspond to 102 is leaf page information. The page information in which the upper three digits of the index correspond to 102 includes an array that stores four records whose index values are 1020, 1021, 1022, and 1023. In this case, a record with an index of 1020 is stored at a position where the value of the least significant digit corresponds to 0.

  The tree type may be a balanced tree such as a B-tree, a B + tree, or a red-black tree, or may be a simple n-ary search tree having no balance.

[3. Add, delete, and search records for content catalog information]
Next, a method for adding a record to catalog information, deleting a record from catalog information, and a method for searching for a record will be described with reference to FIGS.

  When adding or deleting records, it is necessary to update catalog information, that is, page information. At this time, the principle of updating the page information in this embodiment is as follows.

  (1) When adding page information, as well as when updating page information, page information in which the content of the original page information is updated is newly created. For example, when creating page information on the RAM, new page information is created at an address different from the address where the original page information is stored. Also, when updating the root link information, new root link information with updated contents is created.

  (2) When newly creating page information, page numbers are assigned in the order of creation.

  (3) When newly creating page information, a message digest of the new page information is calculated.

  (4) When newly creating root link information, an electronic signature for the new root link information is created.

  (5) The page number and message digest of the newly created page information are set in the parent page information as new link information to the page information. That is, it is necessary to update the parent page information. When the root page information is newly created, the page number and message digest of the root page information are set in the root link information as new link information to the page information. That is, it is necessary to update the root link information.

  (6) The update of page information starts from page information on which a record is added or deleted, and the page information on the path from the page information to the root page information has a long distance from the root page information. Update sequentially from page information. That is, assuming that the root page information is located on the upper side and the leaf page information is located on the lower side, the page information is updated in order from the bottom.

  The principles (1) and (2) are for preventing old page information from being inserted into the catalog information. The principles (3) to (5) are for preventing alteration of the contents of the catalog information. The principle (6) is derived from the principle (5) in order to prevent falsification of catalog information. These principles are only the principles in the present embodiment. For example, as described above, the principle of (1) is not essential in the present invention.

  By creating new page information, old page information, that is, page information that is no longer referenced, may or may not be deleted when it is no longer referenced. Moreover, you may make it delete the page information which became old regularly.

  Based on the above principles, the following explains how to add, delete, and search records.

[3.1 Initial state]
The initial state in the catalog information is a state in which no record is registered, and a state in which the record is ready to be registered. The catalog information in the initial state is created in the root link information registration process executed from the initialization process described later of the center server SA.

  FIG. 3 is a diagram illustrating an example of a catalog information state in an initial state and a state in which catalog information is updated when a record is added.

  As shown in FIG. 3A, first, empty route page information 301 is created. Empty page information means page information in which link information and records are not stored at all. A page number is assigned to the root page information 301. Since the first page information is created, 1 is assigned as the page number. Also, the message digest H1 of the root page information 301 to which the page number is assigned is calculated. When self-link information is included in the page information, the message digest is calculated for the entire page information excluding the part where the message digest of the self-link information is set.

  Next, root link information 101 is created. In the root link information, the page number 1 of the root page information and the message digest H1 are set. Also, the electronic signature 1 of the root link information 101 is created. The electronic signature is created for the entire root link information excluding the part where the electronic signature itself is set. The electronic signature 1 is set in the root link information. The root link information 101 and the root page information 301 constitute an initial state of catalog information.

[3.2 Adding records]
The addition of the record to the catalog information is performed in the record addition process described later of the center server SA. When adding a new record, a new record and a search key for the new record are required. The search key may be specified separately from the new record, or the content ID, content name, etc. set in the new record may be used. Further, a hashed content of the record may be used as a search key.

  Assume that a new record R1 is added in the initial state of catalog information. From the contents of the link information set in the root link information 101, the root page information 301 of page number 1 is referred to. Since the root page information 301 is empty, a record can be added. Therefore, as shown in FIG. 3B, route page information 302 to which the new record R1 is added is newly created. At this time, if necessary, the search key of the new record is added to the root page information 302 as an index of the new record. Then, the latest page number 2 is assigned to the root page information 302, and a message digest H2 is calculated.

  Next, as shown in FIG. 3C, the root link information 102 in which the page number 2 and the message digest H2 are set is newly created. Then, the electronic signature 2 of the root link information 102 is created.

  Next, it is assumed that a new record R2 is added. The number of records stored in the root page information 302 is one. If the number of records that can be stored in the leaf page information is 3, for example, a record can be added to the root page information 302. Therefore, as shown in FIG. 3 (4), route page information 303 is newly created in which a new record R2 is added in addition to the record R1. Then, the latest page number 3 is assigned to the root page information 303, and a message digest H3 is calculated.

  Next, as shown in FIG. 3 (5), the root link information 103 in which the page number 3 and the message digest H3 are set is newly created. Then, the electronic signature 3 of the root link information 103 is created.

  FIG. 4 is a diagram illustrating an example of how catalog information is updated when a record is added.

  A new record R3 is added to the root page information in the same manner as described above. As a result, route page information 304 and route link information 104 storing three records are created.

  Next, it is assumed that a new record R4 is added. Then, as shown in FIG. 4A, the route page information 304 can no longer afford to add a record. Therefore, page information is divided. This division method is arbitrary and varies depending on the type of tree, algorithm, and the like. Therefore, only an example will be described here.

  For example, the content of the root page information 304 is divided into three. As shown in FIG. 4B, leaf page information 305 for storing record R1, leaf page information 306 for storing record R3 and new record R4, and leaf page information 307 for storing record R2 are newly created. Is done. Which leaf page information is newly added to the newly created leaf page information is determined by the search key of the new record. A page number is assigned to each newly created leaf page information, and a message digest is calculated.

  If the parent page information exists in the page information before the division, the division of the page information may end here. However, when the page information before division is root page information, there is no parent page information. Parent page information for storing link information to each divided page information is required. Accordingly, as shown in FIG. 4C, route page information 201 is newly created. In the root page information 201, link information to the leaf page information 305, 306, and 307 is set. When an index is necessary, an index with appropriate contents is set in the root page information 201. Then, the latest page number 8 is assigned to the root page information 201, and a message digest H8 is calculated.

  Next, as shown in FIG. 4 (4), the root link information 104 in which the page number 8 and the message digest H8 are set is newly created. Then, the electronic signature 5 of the root link information 104 is created.

  FIG. 5 is a diagram illustrating an example of how catalog information is updated when a record is added.

  As illustrated in FIG. 5, the catalog information includes root link information 105, root page information 203, node page information 202 that is a child of the root page information 203, and leaf page information 308 that is a child of the node page information 202. Suppose there is. Here, it is assumed that a new record R16 is added. Based on the search key of the record 16 and the index of each page information, for example, the page information for storing the new record R16 in the order of the root link information 105, the root page information 203, the node page information 202, and the leaf page information 308. A search is performed. If a record can be added to the leaf page information 308, new leaf page information 309 that replaces the leaf page information 308 is created. In the leaf page information 309, the record R1 and the new record R16 stored in the leaf page information 308 are set. Then, the latest page number 32 is assigned to the leaf page information 309, and the message digest H32 is calculated.

  As the node page information 202, the link information to the child page information of the node page information 202 is changed, so that new node page information 204 replacing the node page information 202 is created. In the node page information 204, each link information and index stored in the node page information 202 is set. Of the set link information, the page number 24 and the message digest H24 that are link information to the leaf page information 308 are rewritten to the page number 32 and the message digest H32 that are link information to the leaf page information 309. Then, the latest page number 33 is assigned to the node page information 204, and the message digest H33 is calculated.

  As the root page information 203, the link information to the child page information of the root page information 203 is changed, so that new root page information 205 replacing the root page information 203 is created. The method for creating the root page information 205 is the same as the method for creating the node page information 204.

  Then, since the link information to the root page information 203 is changed, new root link information 106 that replaces the root link information 105 is created.

[3.3 Deleting records]
The deletion of the record from the catalog information is performed in a record deletion process described later of the center server SA. When deleting a record, a search key for the record to be deleted is required.

  FIG. 6 is a diagram illustrating an example of how catalog information is updated when a record is deleted.

  It is assumed that the catalog information is in a state after the new record R16 described with reference to FIG. 5 is added. Here, it is assumed that 5 is designated as the search key for the record to be deleted. Based on the search key value 5 and the index of each page information, for example, the root link information 106, the root page information 205, the node page information 204, and the leaf page information 309 shown in FIG. A search is made for page information storing the corresponding record.

  Since the leaf page information 309 stores a record, the index of the record is compared with the search key. The search key value 5 matches the index value 5 of the record R1. Accordingly, new leaf page information 310 is created in place of the leaf page information 309. In the leaf page information 310, records other than the record R1 among the records stored in the leaf page information 308 are set. Then, the latest page number 35 is assigned to the leaf page information 310, and the message digest H35 is calculated.

  Thereafter, node page information 206 replacing the node page information 204, route page information 207 replacing the route page information 205, and route link information 107 replacing the route link information 106 are newly created in this order. The method of creating these page information is the same as that described with reference to FIG.

  Further, assume that 8 is designated as the search key for the record to be deleted. Based on the search key value 8 and the index of each page information, for example, the search is performed in the order of the root link information 107, root page information 207, node page information 206, and leaf page information 310 shown in FIG. . In the leaf page information 310, a record R16 having an index value of 8 is stored. Accordingly, the record R16 is deleted.

  When the record R16 is deleted, the leaf page information 310 becomes empty. Since empty leaf page information is unnecessary, there is no need to create new leaf page information in place of the leaf page information 310. Here, new node page information 208 replacing the node page information 206 is created. In the node page information 208, each link information and index stored in the node page information 206 is set. Of the set link information, the page number 35 and the message digest H35 that are link information to the leaf page information 310 are both rewritten to invalid values. Thereby, the leaf page information 310 is not referred to at all in the future. Then, the latest page number 38 is assigned to the node page information 208, and the message digest H38 is calculated.

  Thereafter, route page information 209 replacing the route page information 207 and route link information 108 replacing the route link information 107 are newly created in this order.

[3.4 Searching records]
The record search is performed in a record search process (to be described later) of the center server SA. When searching for a record, the method for searching for page information storing a record to be searched is the same as the method for searching for a node in a tree structure. That is, the page information search method depends on a search algorithm corresponding to the tree structure of catalog information. A similar search method is also used when adding or deleting records. Hereinafter, an example of a record search method will be described with reference to FIG.

  As shown in FIG. 5, it is assumed that the catalog information includes root link information 106, root page information 205, node page information 204, and leaf page information 309. Here, it is assumed that 8 is designated as the search key of the record to be searched. First, the page number 34 set in the root link information is referenced.

  Since the page number 34 is the page number of the root page information 205, the root page information 205 is referred to next. Here, the search key is compared with each index stored in the root page information 205. The root page information 205 stores 11, 37, and 68 as indexes. When the search key value 5 is compared with the index value 11, the search key value is smaller. Accordingly, the page number 33 included in the link information indicating the page information having an index value smaller than 11 is referred to. In addition to the link information to the page information corresponding to the page number 33, the root page information 205 also stores link information to the page information corresponding to the page numbers 30, 20, and 18. However, in FIG. 5, illustration of page information corresponding to page numbers 30, 20, and 18 is omitted.

  Since the page number 33 is the page number of the node page information 204, the node page information 204 is referred to next. The root page information 205 stores 3 as an index. When the search key value 5 is compared with the index value 3, the search key value is larger. Accordingly, the page number 32 included in the link information indicating the page information having an index value larger than 3 is referred to. The node page information 204 stores link information to page information corresponding to the page number 23 in addition to link information to page information corresponding to the page number 32. However, in FIG. 5, illustration of page information corresponding to the page number 23 is omitted.

  Since the page number 32 is the page number of the leaf page information 309, the leaf page information 309 is referred to next. The leaf page information 309 stores 5 and 8 as indexes. When the search key value 8 and the index are sequentially compared, the index value of the record R16 matches the search key value 8. As a result, the record R16 is searched.

  Note that in this embodiment, tampering is checked when page information is searched for record addition, deletion, and search. This tampering check is performed on the page information to be referred to.

  In the above example, first, the falsification check of the root page information 209 is performed using the message digest H34 set in the root link information 108. Next, the falsification check of the node page information 208 is performed using the message digest H33 set in the root page information 209. Finally, the falsification check of the leaf page information 309 is performed using the message digest H32 set in the node page information 208. Note that the falsification check of the root link information is performed by an initialization process described later of the center server SA.

  In this way, since the tampering check is performed when the page information is actually referred to, the authenticity of the referenced page information is reliably guaranteed. In addition, since the falsification check is performed only on the referenced page information, it is also efficient. However, such a tampering check need not be performed every time a record is added, deleted, or searched. For example, the tampering check may be performed periodically, or the tampering check may be performed when an instruction from the operator is given.

[4. Configuration of center server SA]
Next, the configuration and functions of the center server SA will be described with reference to FIG.

  FIG. 7 is a diagram illustrating a schematic configuration example of the center server SA.

  As shown in FIG. 7, the center server SA includes a control unit 11 including a CPU having a calculation function, a working RAM, a ROM that stores various data and programs, and the like. Further, the center server SA includes a storage unit 12 composed of an HD or the like for storing and storing various data and various programs. Furthermore, the center server SA includes a communication unit 13 for controlling communication of information with the node Nn through the network 8 or the like. Furthermore, the center server SA includes a display unit 14 such as a CRT or a liquid crystal display that displays various types of information. Furthermore, the center server SA includes an input unit (for example, a keyboard, a mouse, etc.) 15 that receives an instruction from the operator and gives an instruction signal corresponding to the instruction to the control unit 11. The control unit 11, the storage unit 12, the communication unit 13, the display unit 14, and the input unit 15 are connected to each other via a bus 16. Here, the input unit 15 is an example of an additional input unit, a deletion input unit, and a search input unit in the present invention. The storage unit 12 is an example of a page information storage unit in the present invention. The storage unit 12 may be a volatile memory or a non-volatile memory.

  The storage unit 12 stores the node ID, IP address, port number, and the like of each node Nn. In addition, a catalog database in which catalog information is registered in units of root link information and page information is constructed in the storage unit 12. Further, the storage unit 12 stores a database management program for managing the catalog database. The database management program is an example of an information generation program.

  The control unit 11 reads and executes a program such as a database management program stored in the storage unit 12 or the like by the CPU, whereby leaf page information generation means, root page information generation means, node page information generation means in the present invention, It functions as root link information generation means, additional input means, additional leaf page determination means, registration means, allocation means, determination means, deleted leaf page determination means, search input means, and search means.

  The database management program may be downloaded from a predetermined server on the network 8, for example, or recorded on a recording medium such as a CD-ROM and read via a drive of the recording medium. You may make it.

[5. Configuration and function of node Nn]
Next, the configuration and function of the node Nn will be described with reference to FIG.

  FIG. 8 is a diagram illustrating a schematic configuration example of the node Nn.

  As shown in FIG. 8, each node Nn includes a control unit 21 as a computer configured by a CPU having a calculation function, a working RAM, a ROM for storing various data and programs, and the like. Each node Nn includes a storage unit 22 composed of an HD (hard disk) or the like for storing and storing various data and various programs, and a buffer memory 23 for temporarily storing a replica of the received content. ing. Further, each node Nn includes a decoder unit 24 that decodes encoded video data (video information), audio data (audio information), and the like included in the content replica. Further, each node Nn performs a predetermined drawing process on the decoded video data and the like, and outputs it as a video signal, and displays a video based on the video signal output from the video processor 25. And a display unit 26 such as a CRT or a liquid crystal display. Further, each node Nn converts the decoded audio data into an analog audio signal by D (Digital) / A (Analog) conversion, and then amplifies this by an amplifier and outputs the audio processing unit 27, and this audio processing unit And a speaker 28 that outputs the audio signal output from the sound wave 27 as a sound wave. Furthermore, each node Nn includes a communication unit 29 for controlling communication of information between other nodes Nn and the like through the network 8. Furthermore, each node Nn includes an input unit (for example, a keyboard, a mouse, a remote controller, an operation panel, or the like) 30 that receives an instruction from the user and gives an instruction signal corresponding to the instruction to the control unit 21. Yes. The control unit 21, the storage unit 22, the buffer memory 23, the decoder unit 24, the communication unit 29, and the input unit 30 are connected to each other via a bus 31. As the node Nn, for example, a personal computer, an STB (Set Top Box), or the like is applicable.

  The storage unit 22 includes a routing table using DHT, an index, an IP address and a port number of a contact node that is an access destination when participating in the content distributed storage system S, and an IP address and a port number of the center server SA. Etc. are stored. The storage unit 22 stores page information acquired from other nodes Nn and page information distributed from the center server SA as files.

  The control unit 21 performs various processes when the CPU reads and executes a program stored in the storage unit 22 or the like.

  For example, when connected to the content distributed storage system S, the control unit 21 acquires the latest root link information and page information from another node Nn. The node Nn as the acquisition destination may be a contact node, for example. Further, the control unit 21 receives the root link information and the page information distributed from the center server SA. The root link information acquired from other nodes Nn or the center server SA is stored in the RAM. Further, the page information acquired from another node Nn or the center server SA is stored in the storage unit 22.

  The control unit 21 searches for content records based on the root link information stored in the RAM and the page information stored in the storage unit 22. This search method is basically the same as the record search method in the center server SA. And the control part 21 performs a required process based on the content of the searched record. For example, the control unit 21 displays the information of the record on the display unit 26, determines whether or not the content is disclosed, and based on the content ID included in the record, the control unit 21 retrieves the content from the content holding node. Or get it.

  The program may be downloaded from a predetermined server on the network 8, for example, or may be recorded on a recording medium such as a CD-ROM and read via a drive of the recording medium. May be.

[6. Operation of Content Distributed Storage System S]
Next, the operation of the distributed content storage system S according to the present embodiment will be described with reference to FIGS.

  In the following description, it is assumed that the catalog information has at least a general n-ary search tree structure. A description of processing specific to the type and structure of the tree is omitted. Also, description of processing related to self-link information that is not essential for page information is omitted.

[6.1 Operation of center server SA]
FIG. 9 is a flowchart illustrating a processing example of the control unit 11 in the center server SA according to the present embodiment.

  The process shown in FIG. 9 is started when the database management program is started, for example. First, the control part 11 performs the initialization process of step S1-S5. Specifically, the control unit 11 determines whether or not a file storing the root link information is stored in the storage unit 12 (step S1). When the database management program is started for the first time, the root link information has not been created yet. On the other hand, if the database management program is not started for the first time, the root link information has already been created and saved in a file. Therefore, when the file storing the root link information is not stored in the storage unit 12 (step S1: NO), the control unit 11 executes a root link information registration process (step S2). In the root link information registration process executed from the initialization process, root link information and root page information are newly created. Details of the root link information registration process will be described later.

  In step S1, when the file storing the root link information is stored in the storage unit 12 (step S1: YES), the control unit 11 reads the root link information from this file and stores it in the RAM (step S1). S3).

  Next, the control unit 11 checks the falsification of the root link information using the electronic signature stored in this file (step S4). For example, the control unit 11 calculates a message digest from the root link information, more specifically, the serial number of the route page information and the message digest. For the calculation of the message digest, a hash function set in the electronic signature is used. Further, the control unit 11 decrypts the signature value of the electronic signature using the public key set in the certificate information of the electronic signature. Then, the control unit 11 determines whether or not the created message digest matches the decrypted data. Here, if they match, the root link information is not falsified, and if they do not match, they are falsified.

  Next, the control unit 11 determines whether or not the root link information has been tampered with (step S5). At this time, if the root link information has been tampered with (step S5: YES), the control unit 11 ends the error. In this case, for example, an error message indicating that the root link information has been tampered with is displayed on the display unit 14, and the execution of the database management program is interrupted.

  In step S5, when the root link information has not been falsified (step S5: NO), or when the root link information registration process in step S2 is completed, the control unit 11 starts the main process.

  First, the control unit 11 determines whether or not there is an end instruction from the operator based on the input from the input unit 15 (step S6).

  In step S6, when there is no termination instruction (step S6: NO), the control unit 11 determines whether or not there is a record addition request from the operator based on the input from the input unit 15 (step S7). ). At this time, if there is a record addition request (step S7: YES), the control unit 11 executes a record addition process (step S8). In this case, the control unit 11 designates a new record input from the input unit 15 by an operator operation, for example. Moreover, the control part 11 also designates the search key of a new record, when a search key is required separately. In this record addition process, the input new record is added to the catalog information. Details of the record addition process will be described later.

  In step S7, when there is no record addition request (step S7: NO), the control unit 11 determines whether there is a record deletion request from the operator based on an input from the input unit 15. (Step S9). At this time, if there is a record deletion request (step S9: YES), the control unit 11 executes a record deletion process (step S10). In this case, the control unit 11 designates a search key for a record to be deleted that is input from the input unit 15 by an operator operation. In this record deletion process, the record to be deleted corresponding to the designated search key is deleted from the catalog information. Details of the record deletion process will be described later.

  In step S9, when there is no record deletion request (step S9: NO), the control unit 11 determines whether there is a record search request from the operator based on the input from the input unit 15. (Step S11). At this time, when there is a record search request (step S11: YES), the control unit 11 executes a record search process (step S12). In this case, the control unit 11 designates a search key input from the input unit 15 by an operator operation. In this record search process, a record corresponding to the specified search key is searched from the catalog information. Details of the record search process will be described later.

  When the process of step S8, S10, or S12 is completed, or when there is no record search request in step S11 (step S11: NO), the control unit 11 proceeds to step S6. And the control part 11 complete | finishes this process, when there exists a termination instruction | indication from an operator in step S6 (step S6: YES).

  FIG. 10 is a flowchart illustrating a processing example in the root link information registration processing of the control unit 11 in the center server SA according to the present embodiment.

  First, the control unit 11 determines whether there is route page information (step S101). That is, the control unit 11 determines whether route page information is stored in the RAM. When the root link information registration process is executed from the initialization process, or when the root page information is deleted from the RAM by the record deletion process, the root page information does not exist. Therefore, when there is no root page information (step S101: NO), the control unit 11 newly creates empty (from) root page information on the RAM. (Step S102).

  Next, the control unit 11 executes a page information registration process (step S103). At this time, the control unit 11 designates newly created route page information. In the page information registration process, link information to the specified page information is created, and this page information is saved in a file. Thereby, route page information is registered. Details of the page information registration process will be described later.

  Next, the control unit 11 sets the created link information as root link information as root link information generation means (step S104).

  In step S101, when the root page information exists (step S101: YES), the control unit 11 determines whether or not the page information pointed to by the current root link information matches the current root page information ( Step S105). In the record addition process or the record deletion process, new root page information is created instead of the old page information pointed to by the current root link information. Therefore, when the page information pointed to by the current root link information does not match the current root page information (step S105: NO), the control unit 11 uses the link information to the root page information as root link information generation means. The root link information is set (step S106).

  When the process of step S104 or S106 is completed, the control unit 11 creates an electronic signature of the root link information as a root link information generating unit (step S107). For example, the control unit 11 creates a message digest from the route link information, more specifically, the page number of the route page information and the message digest. Next, the control unit 11 encrypts the created message digest using the secret key to obtain a signature value. In addition, an electronic signature is created by setting information such as a hash function, a signature value, and certificate information used for calculating the message digest.

  Next, the control unit 11 stores the root link information in a file together with the created electronic signature (step S108).

  Next, the control unit 11 includes the created new root link information in the root link information message and distributes it to all the nodes Nn (step S109). This distribution may be performed by, for example, overlay multicast. In step S105, the control unit 11 ends the root link information registration process when the page information indicated by the current root link information matches the current root page information, or when the process of step S109 is completed.

  FIG. 11 is a flowchart illustrating a processing example in the page information registration processing of the control unit 11 in the center server SA according to the present embodiment.

  First, the control unit 11 assigns the latest page number that has not been assigned to the page information designated as the registration target as the assigning unit (step S151). Next, the control unit 11 calculates a message digest of the page information to be registered (step S152).

  Next, the control unit 11 stores the page information to be registered in a file (step S153). At this time, for example, a page number is added to the file name so that it can be specified where the page information is stored.

  Next, the control unit 11 includes the created new page information in the page information message and distributes it to all the nodes Nn (step S154). This distribution may be performed by, for example, overlay multicast.

  When this process is completed, the control unit 11 ends the page information registration process, and returns link information including the assigned page number and the calculated message digest to the caller process.

  FIG. 12 is a flowchart illustrating a processing example in the record addition processing of the control unit 11 in the center server SA according to the present embodiment.

  First, the control unit 11 acquires the current root link information from the RAM (step S201). Next, the control unit 11 executes a page information acquisition process (step S202). At this time, the control unit 11 specifies root link information. In the page information acquisition process, the page information pointed to by the specified link information is acquired from the file and stored in the RAM. The acquired page information is the page information currently referred to. Details of the page information acquisition process will be described later.

  Next, the control unit 11 determines the assigned page information as an additional leaf page determination unit based on the designated search key and the index set in the currently referenced page information. The assigned page information means page information for storing this record for a certain record. In the case of adding a record, the leaf page information in which the input new record is to be stored is the responsible page information.

  Specifically, the control unit 11 determines whether or not the acquired page information is the page information in charge of the new record (step S203). This determination method depends on the structure of the page information.

  When the acquired page information is not the assigned page information of the new record (step S203: NO), the control unit 11 acquires link information to the next page information from the currently referenced page information ( Step S204). The next page information refers to the page information to be referred to next out of the child page information of the currently referred page information. The page information to be referred to next corresponds to the designated search key. This process is performed according to a search algorithm corresponding to the structure of the search tree of catalog information. For example, the control unit 11 specifies link information to the next page information by comparing a designated search key with an index set for the currently referenced page information. Specifically, in this embodiment, the search key and the index are compared in size. As a result of the size comparison, for example, link information to the next page information is specified when the value of the search key is less than or equal to the value of the index, or when the value of the search key is greater than the value of the index.

  Next, the control unit 11 determines whether there is link information to the next page information (step S205). That is, the control unit 11 determines whether or not link information to the next page information has been acquired. At this time, when the link information to the next page information does not exist (step S205: NO), the control unit 11 creates new assigned page information on the RAM in step S206 as a leaf page information generation unit. . And the control part 11 adds and sets a new record on the produced charge page information as a registration means. At this time, if necessary due to the structure of the catalog information, the control unit 11 sets the search key of the new record as an index and adds it to the assigned page information in association with the new record. For example, when leaf page information becomes empty due to a record being deleted in a record deletion process to be described later, the empty leaf page information is deleted. In this case, in the parent page information of the leaf page information which has become empty, an invalid value is set for the link information pointing to the leaf page information. As a result, link information pointing to empty leaf page information is deleted. However, if the index stored in the parent page information is not particularly updated, invalid link information may be identified by comparing the search key and the index thereafter. That is, in step S205, it is determined that there is no link information to the next page information. In this case, since the next page information, that is, responsible page information for storing a new record corresponding to the search key is required, this responsible page information is created in step S206.

  On the other hand, when the link information to the next page information exists (step S205: YES), the control unit 11 proceeds to step S202. At this time, the control unit 11 specifies the acquired link information and executes page information acquisition processing.

  In step S203, when the acquired page information is assigned page information of a new record (step S203: YES), the control unit 11 can add a new record to the determined assigned page information as a determination unit. It is determined whether or not. Specifically, the control unit 11 determines whether or not records in the assigned page information are already stored up to the upper limit of the number of records that can be stored (step S207). At this time, when the record up to the upper limit of the number of records that can be stored is not stored (step S207: YES), the control unit 11 serves as the leaf page information generation unit in step S208 in the current assigned page information. New responsible page information in which the contents are copied is created on the RAM. And the control part 11 adds and sets a new record to new charge page information as a registration means. At this time, the control unit 11 additionally sets a search key for a new record as an index as necessary, as in step S206.

  On the other hand, when the record has already been stored up to the upper limit of the number of records that can be stored (step S207: NO), the control unit 11 divides the page information as a leaf page information generation unit in step S209. Specifically, the control unit 11 creates a plurality of new page information on the RAM by dividing the content of the current assigned page information according to the division algorithm corresponding to the structure of the catalog information search tree. And the control part 11 adds and sets a new record to the charge page information among this new page information as a registration means. For example, when the content of the assigned page information is divided into three, the records stored in the original assigned page information are divided into the first half, the middle, and the second half of the record in the order of the index. For example, assume that six records with index values 1, 2, 3, 4, 5, and 6 are stored in the original assigned page information. When these records are equally divided into three, the records with index values 1 and 2 are the first half records, the records with index values 3 and 4 are the middle records, and the records with index values 5 and 6 are It becomes the second half record. Then, page information for storing each record is created. Which page information the new record is stored in is determined based on the search key. Further, the control unit 11 additionally sets a search key for a new record as an index as necessary, as in step S206.

  After creating a new assigned page in step S206, S208 or S209, the control unit 11 executes page information registration processing (step S210). At this time, the control unit 11 designates newly created page information. In the page information registration process, link information to the specified page information is generated, and this page information is saved in a file. As a result, page information is registered. In step S209, when the assigned page information is divided into a plurality of new page information, a page information registration process is executed for each of the plurality of page information.

  Next, the control unit 11 determines whether there is parent page information of the registered page information (step S211). For example, whenever there is link information to the next page information in the determination in step S205, the page number of the page information referred to at that time may be stored in a predetermined area of the RAM. By referring to the predetermined area, it is possible to specify whether parent page information exists and the page number of the parent page information.

  When the parent page information exists (step S211: YES), the control unit 11 serves as an additional update unit, and the page number of each section page information from the parent page information of the newly created leaf page information to the root page information. And update the message digest. Specifically, as the root page information generation unit and the node page information generation unit, parent page information is created in which a message digest of child page information and link information including the page number of the child page information are stored. More specifically, the control unit 11 creates new parent page information in which the content of the original parent page information is copied on the RAM (step S212). Then, the control unit 11 sets page information that currently refers to the new parent page.

  Next, the control unit 11 rewrites the link information indicating the old child page information stored in the page information currently referred to to the link information indicating the new child page information (step S213). Specifically, the control unit 11 sets the link information generated by the page information registration process in step S210 as link information indicating new child page information. Then, the control unit 11 overwrites the link information indicating the new child page information with the link information indicating the old child page information.

  Next, the control unit 11 proceeds to step S210. At this time, the control unit 11 designates the newly created page information that is currently referred to, and executes the page information registration process. As a result, the currently referenced page information is registered.

  In step S211, if the parent page information of the registered page information does not exist, that is, if the registered page information is the root page information (step S211), the control unit 11 performs the root link information registration process. Execute (Step S214). In the root link information registration process, root link information indicating the registered new root page information is created. When finishing the root link information registration process, the control unit 11 ends the record addition process.

  FIG. 13 is a flowchart illustrating a processing example in the record deletion processing of the control unit 11 in the center server SA according to the present embodiment.

  First, the control part 11 performs the process of step S251-S255. These processes are the same as the processes in steps S201 to S205 in the record addition process. That is, the control unit 11 acquires the current root link information from the RAM (step S251). Next, the control unit 11 executes a page information acquisition process (step S252). Next, the control unit 11 determines the responsible page information based on the designated search key and the index set in the node page information as a deleted leaf page determination unit. Specifically, the control unit 11 determines whether or not the acquired page information is the assigned page information of the record to be deleted corresponding to the designated search key (step S253). When the acquired page information is not the assigned page information of the deletion target record (step S253: NO), the control unit 11 acquires link information to the next page information from the currently referred page information. (Step S254). Next, the control unit 11 determines whether there is link information to the next page information (step S255). At this time, if there is no link information to the next page information (step S255: NO), the control unit 11 ends the record addition process. That is, since there is no page information storing the record to be deleted, the record addition process ends here.

  In step S253, when the acquired page information is the assigned page information of the deletion target record (step S253: YES), the control unit 11 determines whether or not the assigned page information stores the deletion target record. (Step S256). This determination method depends on the structure of the catalog information. For example, in the case where the record is associated with the index of the record and stored in the page information, the index stored in the assigned page information is searched with the specified search key. If there is an index that matches the specified search key, it is determined that the record to be deleted is stored. On the other hand, if there is no index that matches the designated search key, it is determined that the record to be deleted is not stored. When the assigned page information does not store the deletion target record (step S256: NO), the control unit 11 ends the record deletion process.

  On the other hand, when the assigned page information stores a record to be deleted (step S256: YES), the control unit 11 creates leaf page information storing one or more records as a leaf page information generation unit. To do. Specifically, in step S257, the control unit 11 creates new assigned page information on the RAM by copying the contents of the current assigned page information. Then, the control unit 11 deletes the deletion target record from the new assigned page information. At this time, if the index of the record to be deleted is set in the assigned page information, the control unit 11 also deletes this index.

  Next, the control unit 11 determines whether or not the number of records stored in the created new page information and the number of link information are both 0 (step S258). That is, the control unit 11 determines whether or not the created new page information is empty. At this time, if the created new page information is not empty (step S258: NO), the control unit 11 designates this page information and executes a page information registration process (step S259). Thereby, new page information from which the deletion target record is deleted is registered.

  On the other hand, when the created new page information becomes empty (step S258: YES), the control unit 11 deletes the page information determined to be empty in step S258 from the RAM (step S260).

  The control part 11 will perform the process of step S261-S264, after finishing the process of step S259 or S260. These processes are basically the same as the processes in steps 211 to S214 in the record addition process.

  That is, the control unit 11 determines whether there is page information registered in step S259 or parent page information of the page information deleted in step S260 (step S261). When the parent page information exists (step S261: YES), the control unit 11 serves as a deletion update unit, and the page number of each section page information from the parent page information of the newly created leaf page information to the root page information. And update the message digest. Specifically, the control unit 11 creates parent page information in which a message digest of child page information and link information including the page number of the child page information are stored as root page information generation means and node page information generation means. To do. More specifically, the control unit 11 creates new parent page information in which the content of the original parent page information is copied on the RAM (step S262). Then, the control unit 11 sets page information that currently refers to the new parent page.

  Next, the control unit 11 rewrites the link information indicating the old child page information stored in the page information currently referred to to the link information indicating the new child page information (step S263). However, when the child page information has been deleted in step S260, the control unit 11 rewrites the link information that has pointed to the old child page information to a state that does not indicate anything. For example, invalid values are set for the page number and the message digest. Next, the control unit 11 proceeds to step S261. In step S261, when there is no parent page information of the registered page information (step S261: NO), the control unit 11 executes a root link information registration process (step S264). When finishing the root link information registration process, the control unit 11 ends the record deletion process.

  FIG. 14 is a flowchart illustrating a processing example in the page information acquisition processing of the control unit 11 in the center server SA according to the present embodiment.

  First, the control unit 11 determines whether or not the designated link information indicates valid page information (step S301). For example, when the page number of the link information is set to an invalid value, this link information does not indicate valid page information. For example, when the page number is determined to start from 1, link information in which a value of 1 or more is set for the page number is valid, and link information in which the page number is set to 0 is invalid. . At this time, if the specified link information does not indicate valid page information (step S301: NO), the control unit 11 ends the page information acquisition process. In this case, information that there is no page information is returned to the caller process.

  On the other hand, when the designated link information indicates valid page information (step S301: YES), the control unit 11 reads the page information from the file indicated by the page number included in the link information and stores it in the RAM. Store (step S302).

  Next, the control unit 11 checks the read page information for falsification using the message digest included in the designated link information (step S303). Specifically, the control unit 11 calculates a message digest of the read page information. For the calculation of the message digest, the same hash function as that used when the message digest is calculated in the page information registration process is used. Then, the control unit 11 determines whether or not the calculated message digest matches the message digest included in the specified link information. Here, if they match, the root link information is not falsified, and if they do not match, they are falsified.

  Next, the control unit 11 determines whether or not the read route page information has been tampered with (step S304). At this time, if the page information has been tampered with (step S304: YES), the control unit 11 ends the error. In this case, for example, an error message indicating that the page information has been tampered with is displayed on the display unit 14, and the execution of the database management program is interrupted.

  On the other hand, when the page information has not been tampered with (step S304: NO), the control unit 11 returns the read page information to the caller process, and ends the page information acquisition process.

  FIG. 15 is a flowchart illustrating a processing example in the record search processing of the control unit 11 in the center server SA according to the present embodiment.

  First, the control part 11 performs the process of step S351-S355. These processes are the same as the processes in steps S201 to S205 in the record addition process. That is, the control unit 11 acquires the current root link information from the RAM (step S351). Next, the control unit 11 executes a page information acquisition process (step S352). Next, the control unit 11 determines the responsible page information based on the designated search key and the index set in the node page information as a search means. Specifically, the control unit 11 determines whether or not the acquired page information is assigned page information of a record corresponding to the designated search key (step S353). When the acquired page information is not the assigned page information of the deletion target record (step S353: NO), the control unit 11 acquires link information to the next page information from the currently referred page information. (Step S354). Next, the control unit 11 determines whether there is link information to the next page information (step S355). At this time, if the link information to the next page information does not exist (step S355: NO), the control unit 11 presents to the operator that a record corresponding to the designated search key has not been found ( Step S356). For example, a message indicating that it was not found is displayed on the display unit 14.

  In step S353, when the acquired page information is the assigned page information of the record corresponding to the search key (step S353: YES), the assigned page information stores the record corresponding to the search key. It is determined whether or not (step S357). At this time, if the assigned page information does not store the record corresponding to the search key (step S357: NO), the control unit 11 indicates that the record corresponding to the designated search key has not been found. (Step S356). On the other hand, when the assigned page information stores a record corresponding to the search key, the control unit 11 presents the information of the found record to the operator. For example, the contents of the record are displayed on the display unit 14. When the process of step S356 or step S358 is completed, the control unit 11 ends the record search process.

[6.2 Operation of node Nn]
FIG. 16 is a flowchart illustrating a processing example of the control unit 21 in the node Nn according to the present embodiment.

  The process shown in FIG. 16 is started when, for example, the node Nn participates in the content distributed storage system S. First, the control unit 21 acquires the latest root link information and page information from other nodes Nn participating in the content distributed storage system S (step S501). For example, the control unit 21 receives the root link information and the page information transmitted from the requested node Nn by transmitting a message to the requested node Nn. Then, the control unit 21 stores the root link information in the RAM and saves the page information in a file.

  Next, the control unit 21 determines whether there is an end instruction from the user based on the input from the input unit 30 (step S502).

  In step S502, when there is no termination instruction (step S502: NO), the control unit 21 determines whether there is a record search request from the user based on the input from the input unit 30 (step S503). ). At this time, if there is a record search request (step S503: YES), the control unit 21 executes a record search process (step S504). In this record search process, a record corresponding to the search key designated by the user is searched from the catalog information. Since the contents of the record search process are the same as the contents of the record search process in the center server SA, detailed description thereof is omitted.

  In step S503, when there is no record search request (step S503: NO), the control unit 21 determines whether or not a root link information message has been received (step S505). At this time, when receiving the root link information message (step S505: YES), the control unit 21 sets the information included in the root link information message in the RAM as root link information (step S506).

  In step S505, when the root link information message is not received (step S505: NO), the control unit 21 determines whether a page information message is received (step S507). At this time, when the control unit 21 receives the page information message (step S507: YES), the control unit 21 stores the information included in the page information message in the file as page information (step S508).

  When the process of step S504, S506, or S508 is completed, or when the page information message is not received in step S507 (step S507: NO), the control unit 21 proceeds to step S502. Then, when there is an end instruction from the user in step S502 (step S502: YES), the control unit 11 ends this process.

  As described above, according to the present embodiment, the control unit 11 creates leaf page information in which one or more records are stored. In addition, the control unit 11 creates root page information in which a message digest of child page information of the root page information and link information including the page number of the child page information are stored. Further, the control unit 11 creates node page information in which a message digest of child page information of node page information other than the root page information and link information including the page number of the child page information are stored. Then, the control unit 11 stores the created leaf page information, root page information, and node page information in the storage unit 12 as a tree structure.

  Therefore, by managing records in a tree structure, it is possible to check for falsification of records and to reduce the time for record search processing.

  Also, the control unit 11 creates root link information in which a message digest of root page information, a page number of root page information, and an electronic signature of root link information are stored. Then, the control unit 11 stores the created root link information in the storage unit 12.

  Therefore, in the past, it was necessary to apply an electronic signature to all the records, but by applying an electronic signature only to the root link information, the electronic signature of the root page is guaranteed in order to guarantee tampering of the record located in the child. By confirming, you can confirm. For this reason, the data amount of each record is reduced while an electronic signature is assigned to each record. In addition, since a process for applying an electronic signature to each record is not necessary, an electronic signature process becomes unnecessary.

  In addition, the control unit 11 determines the assigned page information based on the search key input from the input unit 15 and the index set in the node page information. Further, the control unit 11 determines whether or not a new record can be added to the determined assigned page information. If a new record can be added, the control unit 11 creates new leaf page information in which the new record is additionally set in the content of the determined assigned page information. On the other hand, when a new record cannot be added, the control unit 11 creates new leaf page information and additionally sets the new record as new leaf page information. Then, the control unit 11 updates the page number and message digest of each section page information from the parent page information of the newly created leaf page information to the root page information. Moreover, when the deletion target record is stored in the determined leaf page information, the control unit 11 creates new leaf page information from which the deletion target record is deleted. Then, the control unit 11 updates the page number and message digest of each section page information from the parent page information of the newly created leaf page information to the root page information.

  Therefore, a record can be easily added to the leaf page information in the tree structure. Further, even if a new record cannot be added to the assigned page information, a new record can be added to the newly added leaf page information.

  In addition, the control unit 11 determines the assigned page information based on the search key input from the input unit 15 and the index set in the node page information. In addition, when a deletion target record is stored in the determined assigned page information, the control unit 11 creates new leaf page information in which the deletion target record is deleted. Then, the control unit 11 updates the page number and message digest of each section page information from the parent page information of the newly created leaf page information to the root page information.

  Therefore, for example, it is possible to eliminate a record that becomes old and is to be deleted.

  Further, the control unit 11 determines the assigned page information based on the search key input by the input unit 15 and the index set in the node page information. When the search target record is stored in the determined assigned page information, the control unit 11 presents information on the search target record to the operator.

  Therefore, a search target record can be quickly searched.

  In the above embodiment, the management apparatus according to the present invention is applied to a server apparatus in a peer-to-peer system, but may be applied to a server apparatus in a client-server system, for example.

  Further, the present invention is not limited to searching for content catalog information. It can also be applied as a general-purpose database record and index.

3 IX
4a, 4b ISP
5a, 5b DSL line dealer apparatus 6 FTTH line dealer apparatus 7 communication line 8 network 9 overlay network 11 control section 12 storage section 13 communication section 14 display section 15 input section 16 bus 21 control section 22 storage section 23 buffer memory 24 decoder Unit 25 video processing unit 26 display unit 27 audio processing unit 28 speaker 29 communication unit 30 input unit 31 bus Nn node SA center server S content distributed storage system

Claims (8)

A page information storage means for storing a plurality of page information as a tree structure in association with the root page information located at the root to the leaf page information located at the leaf;
Leaf page information generating means for generating the leaf page information including one or more records;
Serial of child page information at the child position of the root page information or falsification check information for checking falsification of the record at the child position of the root page information and child page information at the child position of the root page information Root page information generating means for generating the root page information including a number;
Tamper check information for checking tampering of the child page information of the node page information located between the root page information and the leaf page information or tampering of the record at the child position of the node page information; Node page information generating means for generating the node page information including a child page information serial number at a child position of the node page information;
With
The page information storage means stores the root page information, the node page information, and the leaf page information in the tree structure. Generate root link information composed of a serial number of the root page information, falsification check information for checking falsification of the root page information, and an electronic signature for checking falsification of the root link information. A root link information generating means;
The management apparatus according to claim 1, wherein the page information storage means stores the root link information, the root page information, the node page information, and the leaf page information in the tree structure. . The root page information generation means further generates responsible area information indicating a responsible area of index information corresponding to one or a plurality of page information having a parent-child relationship with the root page information as a parent in the tree structure. ,
The node page information generation means further generates assigned region information indicating an assigned region of index information of one or more page information having a parent-child relationship with the node page information as a parent in the tree structure,
An additional input means for inputting an additional record to be added and index information of the record;
Additional leaf page determining means for determining the leaf page information for registering the additional record, based on the index information input by the additional input means and the assigned area information of the root page information or the node page information; ,
Registration means for registering the additional record in the leaf page information determined by the additional leaf page determination means;
Assigning means for assigning a new serial number to the leaf page information determined by the additional leaf page determining means;
Additional update means for updating the serial number and the check information of the node page information and the root page information from the leaf page information to which the additional record is registered to the root page information based on the registration of the additional record When,
The management apparatus according to claim 1, further comprising: The additional page determining means includes a determining means for determining whether the additional record can be registered in the determined leaf page information.
When the determination unit determines that the additional record cannot be registered, the leaf page information generation unit generates new leaf page information,
The registration means registers the additional record in the newly generated leaf page information,
The assigning means assigns a new serial number to the newly generated leaf page information,
The additional update means, based on registration of the additional record, the serial number and the check information of the node page information and the root page information from the newly generated leaf page information to the root page information. The management apparatus according to claim 3, wherein the management apparatus is updated. The root page information generation means further generates responsible area information indicating a responsible area of index information of page information having a parent-child relationship with the root page in the tree structure as a parent,
The node page information generation means further generates assigned region information indicating an assigned region of index information of page information in a parent-child relationship with the node page information as a parent in the tree structure,
A deletion input means for inputting index information of a deletion record to be deleted;
Deleted leaf page determination means for determining the leaf page information for registering the deletion record, based on the index information input by the deletion input means and the assigned area information of the root page information or the node page information; ,
Updating the serial number and the check information of the node page information and the root page information from the leaf page information to the root page information determined by the deleted leaf page determination means based on the determination of the leaf page information Delete and update means,
The management apparatus according to any one of claims 1 to 4, further comprising: The leaf page information includes index information for searching for the record included in the leaf page information,
The root page information generation means further generates responsible area information indicating a responsible area of index information of page information having a parent-child relationship with the root page in the tree structure as a parent,
The node page information generation means further generates assigned region information indicating an assigned region of index information of page information in a parent-child relationship with the node page information as a parent in the tree structure,
Search input means for inputting index information of search records to be searched;
Search means for searching index information of the search record based on the index information input by the search input means and the assigned area information of the root page information or the node page information;
The management apparatus according to any one of claims 1 to 5, further comprising: In order to manage a plurality of page information as a tree structure, the child page information at the child position of the root page information located at the root in the tree structure or the falsification for checking the falsification of the record at the child position of the root page information A root page information generation step for generating the root page information including check information and a serial number of the child page information at a child position of the root page information;
A leaf page information generation step for generating leaf page information including one or more records;
Falsification for checking the falsification of the child page information at the child position of the node page information located between the root page information and the leaf page information or the record at the child position of the node page information in the tree structure A node page information generating step for generating the node page information including check information and a serial number of the child page information at a child position of the node page information;
A page information storage step of storing the root page information, the node page information, and the leaf page information as the plurality of page information in the tree structure;
Information generation program for realizing the above on a computer. In order to manage a plurality of page information as a tree structure, the child page information at the child position of the root page information located at the root in the tree structure or the falsification for checking the falsification of the record at the child position of the root page information A root page information generation step for generating the root page information including check information and a serial number of the child page information at a child position of the root page information;
A leaf page information generation step for generating leaf page information including one or more records;
Falsification for checking the falsification of the child page information at the child position of the node page information located between the root page information and the leaf page information or the record at the child position of the node page information in the tree structure A node page information generating step for generating the node page information including check information and a serial number of the child page information at a child position of the node page information;
A page information storage step of storing the root page information, the node page information, and the leaf page information as the plurality of page information in the tree structure;
An information generation method comprising:

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